Methods using a chemical reaction on a substrate, such as chemical vapor deposition method (refer to PTL 1) and atomic layer deposition method (refer to PTL 2), are well known as methods for uniformly depositing a thin film on a substrate having a relief structure. These methods are used for coating of a bottom surface and an inner wall surface of a deeply bottomed trench or hole. However, the methods using the chemical reaction are not suitable for applications requiring a metal film of high purity, due to the fact that a reactive gas in the course of processing gets mixed in the film. Further, only very limited materials have so far been put into use for metal films because development time is required to search for a source gas as a source of the chemical reaction. Therefore, the methods are not used for purposes of deposition of multilayered films of various kinds of metal films or alloy films.
Remote low-pressure sputtering (refer to PTL 3), bias sputtering (refer to PTL 4) and the like are known as conventional technologies for the coating of the bottom surface and the inner wall surface of the trench or the hole by physical vapor deposition method. However, the remote low-pressure sputtering and the bias sputtering inherently have the problem of involving poor uniformity in film thickness in a substrate surface, because a target surface is arranged substantially parallel to and opposite to the substrate surface.
Also known is an example of sputtering method in which coating properties on the bottom surface and the inner wall surface of the hole are improved by depositing a film while appropriately varying the angle of the substrate being rotated (refer to PTL 5), which, however, is inadequate for an improvement in film thickness distribution in the substrate surface. For a method for improving the film thickness distribution as well as improving the coating properties by appropriately varying the angle of the substrate being rotated, a mask called a shaper needs to be provided immediately above the substrate to control the amount of incident sputter particles, as illustrated in an example of ion beam sputter deposition method disclosed in PTL 6. However, the use of the mask poses the problem of particle generation from a film peeling off from the mask because the film is deposited on the mask with time.
Meanwhile, a deposition method with oblique incidence and rotation disclosed in PTL 7 is known as a method for uniformly depositing a thin film on a flat surface.
In this method, a cathode unit supporting a target is arranged offset from a substrate, i.e., obliquely above the substrate, and a target material is sputtered by magnetron sputtering while the substrate is rotated along its process target surface.
Further, as for the deposition method with oblique incidence and rotation, there is disclosed a method for controlling the rotation speed of a substrate in order to reduce unevenness in film thickness distribution of a magnetic film formed in a magnetic field (refer to PTL 8).